Furnace construction with roof section removal means



May.12,- 197o. c. B.GENTRQY 3,s; 1,4s3

FURNACE CONSTRUCTION WITH ROOF SECTION REMOVAL MEA S Fii ed Oct. 21,'1968 2 Sheets-Sheet 2 INVENTOR CHARLES B. GEN'T'RY I BY ATTORNEYSUnited States Patent 3,511,483 FURNACE CONSTRUCTION WITH ROOF SECTIONREMOVAL MEANS Charles B. Gentry, Grand Rapids, Mich., assignor to'Granco Equipment, Inc., Grand Rapids, Mich., a corporation of DelawareFiled Oct. 21, 1968, Ser. No. 769,014 Int. Cl. F27b 9/32; F27d J/18 U.S.Cl. 263-6 8 Claims ABSTRACT OF THE DISCLOSURE This disclosure relates toa furnace construction with easily removable roof sections. A billetheating furnace has a longitudinal heating chamber through which billetsare passed from an entrance to an exit end. Billets are heated by directflame impingement on the billets. Hot gases are withdrawn through thetop of refractory sections which form the sides and top of the heatingchamber. A casing which is spaced from the refractory section enclosesthe furnace. The hot gases from the heating chamber are withdrawnthrough exhaust conduits extending down from the top of the externalcasings above each refractory section. Bottom portions of the exhaustconduits are removable to permit each furnace section to be lifted andmoved above adjacent furnace sections. Movable hoist means are providedwithin the casing for lifting the furnace sections and moving the liftedsections above the adjacent sections so that rapid access can beobtained to the heating chamber interior. Means are provided on therefractory sections for engaging the hoist members so that the sectionscan be easily raised.

This invention relates to billet heating furnaces having an externalcasing with built-in means for lifting the furnace sections for rapidaccess to the interior of the furnace.

In the extrusion of longitudinal members from metals such as aluminum,for example, heated billets are pressed through a die considerablysmaller than the billets. The billets are heated in order to facilitatethe extrusion.

A furnace has recently been developed to heat billets rapidly andseriatim. The furnace has a longitudinal chamber which is relativelysmall in cross-section. The billets are conveyed or pushed through thelongitudinal chamber from an entrance end to an exit end. The billetsare rapidly heated by direct impingement of flames from a plurality ofburner tiles spaced along the longtiudinal chamber between the entranceand exit ends. The hot gases generated within the furnace must beremoved by an exhaust system in order to maintain effective heating ofthe billets. A spaced external casing is provided with exhaust conduitsextending from the interior of the longitudinal chamber through therefractory walls and through the external casing to a point exteriorallyof the building in which the furnace is located. The spaced externalcasing is highly desirable to prevent oil fires from hydraulic fluid andto minimize the danger of burns to employees.

Due to operators errors and for various other reasons, a billet canbecome blocked within the chamber and/or a melt down can occur. Whenthis happens, the furnace must be shut down and direct access must beobtained to the section of the furnace which contains the blocked billetor the melt down in order to clear out the problem. Other problems ofrepair to the interior of the furnace can occur and direct access mustalso be obtained to that portion of the furnace. Since the furnacechamber is relatively small in cross-section, access to the interiorthrough the entrance or exit is not feasible. The external casing andthe exhaust system preclude the use of an ice overhead crane for removalof the various furnace sectrons.

It has been proposed to make the furnace in sections and to use a forklift truck, for example, to remove different upper sections of thefurnace after portions of the exterior casing have been removed. Thefork lift truck, however, causes damage to the refractory portions ofthe furnace. Further, there is usually not enough space in the plant topermit a fork lift truck to move alongside the furnace so as to removethe damaged sections.

The invention of this application seeks to overcome these prior artproblems by making the furnace with removable upper sections, providinghoist means between the furnace and the exterior casing, and providingan effective exhaust system which can be adapted to permit removal ofthe furnace sections for repairs and reconstruction.

By various aspects of this invention one or more of the following, orother, objects can be obtained.

It is an object of this invention to provide a longitudinal billetheating furnace having means to provid quick access to the interiorportions thereof.

It is a further object of this invention to provide a billet heatingfurnace in which billets are heated by direct flame impingement, thefurnace having an adequate ventilation system wherein rapid access tothe interior of the furnace is provided without damaging furnacecomponents.

It is yet another object of this invention to provide an improved billetheating furnace with easily removable furnace sections which aretransportable along the furnace and easily replaceable with a minimum ofdown time.

Other aspects, objects, and the several advantages of this invention areapparent to one skilled in the art from a study of this disclosure, thedrawings, and the appended claims.

According to the invention there is provided a billet heating furnacehaving a longitudinal heating chamber formed from a plurality of upperrefractory sections and lower refractory sections. The longitudinalheating chamber has an entrance end and an exit end. Heating means arespaced along the side of the furnace for heating the billets within theheating chamber by direct impingement of the flame on the billets. Meansare provided for passing the billets through the heating chamber fromthe entrance end to the exit end. A casing surrounds the furnace andincludes a top and side walls. Gas removal means are provided forwithdrawing the removing gases within the furnace through the top of theupper refractory sections and through the casing top.

Means are provided within the casing to raise individual upperrefractory sections so that direct access can be had to the furnaceinterior. Preferably, the raising means comprises a track means withinthe casing extending longitudinally of the furnace and hoist meansmovably supported by the track so as to be longitudinally movable abovethe furnace. A cable is provided on the hoist having an end raisable andlowerable by the hoist. Means on the upper refractory sections areprovided for engaging the end of the cable so that the upper refractorysections can be raised by raising the end of the cable.

The gas removable means are constructed so as to per- .mit raising thefurnace sections and moving each longitudinally of the furnace above thetop of the other furnace sections.

The invention will now be described with reference to the accompanyingdrawings, in which:

FIG. 1 is a perspective view of a furnace construction embodying theinvention with the side wall partly broken away; i

FIG. 2. is a side elevational view in section of the furnace shown inFIG. 1; and

FIG. 3 is a cross-sectional view taken along lines IIL-III of FIG. 2.

Referring now to the drawings, the furnace is enveloped by an outercasing 12 with an exhaust collector duct 13 forming a roof. The outercasing 12 has removable side Wall panels 12a which are retained bydownwardly extending flanges 15 at the top upwardly extending flanges 17at the bottom of the panels. The furnace comprises an upper furnacesection 14, a burner section 16 and a lower furnace section 18. Thefurnace is supported by cross beams 20, longitudinal beams 22 and risers24.

The furnace forms a longitudinal heating chamber 16 for heating thebillets 32 shown in phantom lines in the drawings.

The billets are supported within the longitudinal heating chamber 26 onrollers 30 rotatably supported by channel members 28. The billets areheated by flames which are projected from burner tiles 36. Fuel lines 34supply fuel to the burner tiles 36. The flames from the burner tilesimpinge directly on the billets and envelop the billets.

The lower furnace section 18 is encased by a metal bottom casing 38having outwardly extending flanges 40 at the top portion thereof. Holesare provided in the casing 38 for the passage of the fuel lines 34.

v The upper furnace section 14 has a refractory portion 42 with anexhaust aperture 44. A metal casing 46 is fixed to the outer portion ofthe refractory 42 by embedded connecting rods 48. The metal casing 46has an outwardly extending flange 50 adjacent flange 40 of the bottomcasing. The metal casing 46 has brace members 52 which are coextensivewith the sides of the casing as seen in FIG. 3. Brace bars 64 are fixedto adjacent brace members 52 in a given furnace section. Support rods 66having anchors 68 embedded in the refractory are positioned beneath thebrace bars 64 and extend outwardly at the sides of the upper furnacesections 14. Each sup port rod 66 has a downwardly turned handle.

The furnace is made from a plurality of furnace sections comprisingrefractory portions 42 and metal casings 46. Each refractory portion hasbeveled corners 54, leaving a small open area around the edge of eachsection. This open area is filled with a loose refractory fillermaterial 56 and is covered by a cover plate 58. The cover plate has anoutwardly directed flange to which bolts'62 are attached and throughwhich bolts 62 the cover plate is secured to the flange 40 of the metalbottom casing 38. The cover plate overlaps the edges of the meal casing46. Each brace member 52 is spaced 2 suflicient distance from the edgeof the furnace section 14 to permit the cover plate 58 to slidelaterally on a section 14 so that adjacent sections can be lifted andremoved without interference from the cover plate 58.

Upright support members 70- having cross beam members 72 support I-beamrails 74 which extend longitudinally within the furnace. Overheadtrolley hoists 76 ride on the rails and are adapted to raise individualupper furnace sections 14 within the external casing. The trolley hoists76 comprise wheels 78 rotatably secured to depending arms 80. An eyelet82 is fixed at the bottom of arms for a hook 84. A hoist 86 is fixed tothe hook 84 and carries a cable 88 with a loop 90 for engaging thesupport rods 66.

Exhaust conduits 92 are positioned above the exhaust apertures 44 forremoving the hot gases from the interior of the furnace. Each exhaustconduit communicates with the exhaust colector duct 13. A fan 94 isprovided to withdraw the hot gases from the exhaust collector duct 13.

Each exhaust conduit 92 has an extension 93 fixed at the bottom thereofthrough a machine screw 98. A damper valve is positioned within theextension 93 and has a handle 102 for adjusting the position of thevalve 100 to regulate the flow of gases through the exhaust conduit 92.The extension 93 is adjustable so that the distance from the bottom ofthe extension 93 to the top of the refractory section 14 can beadjusted. The bottom of extension 93 is spaced from the top of therefractory section to permit ambient air to be drawn into the conduit tocool the same. By this system, the gases being withdrawn from thefurnace are cooled to 400- 500 F, thereby eliminating the need forinsulated ducts. The bottom of the extension is spaced close enough tothe top of the refractory section 14 to provide enough draft to keep thegasses moving through the furnace and while keeping the exhaust conduitat a desired temperature.

The upper portion of exhaust conduit 92 has outwardly directed flanges104 at the exhaust collector duct 13. The exhaust conduit 92 issupported through flanges 104 by angle bar supports 106 which are fixedon the bottom of the exhaust collector duct 13. In this manner, theexhaust conduit 94 can be easily removed in order to permit lifting ofthe refractory section 14.

In this kind of furnace wherein the billets are heated by direct flameimpingement, a high flow of gases is required. The hot gases must becontinually withdrawn through the top of the furnace through conduits92. The external casing minimizes the danger of fire due to oil whichmay be exposed to the hot burners. The external casing further preventsdissipation of heat into the area surrounding the furnace during normaloperation of the furnace.

In operation, when it is desirable to obtain access to the interiorportions of the furnace, the side walls 12a of the casing 12 areremoved. The exhaust conduit 92 above the section to be removed isforced toward the front or back of the furnace to disengage flanges 104from the angle bar supports 106. The exhaust conduit 92 can then belowered and removed. In a similar manner, the exhaust conduit adjacentthe section to be removed is also removed. The hoists 76 are positionedoverhead of the upper section to be removed. Bolts 62 of cover plate 58on either side of the section to be removed are loosened so that thecover plates can be moved to adjacent sections. The cover plates 58 arethen moved laterally to free the upper furnace section to be moved. Theloops 90 of cable 88 are then positioned over the lift bars 66 in amanner which has been illustrated in FIG. 1. The hoists are activated toraise the furnace section to a position illustrated by phantom lines inFIG. 3. The furnace section, being wholly supported by the trolley, canbe wheeled along the length of the furnace by the trolleys to open thefurnace for repairs. If desirable, all lower portions of conduits 92 canbe removed and the furnace section 14 can be wheeled down to the end ofthe track for removal from the hoist by lift truck or similar article. Anew furnace section can then be positioned on the hoist and lowered inplace to replace the removed furnacesection. The open areas between thefurnace section are then filled with filler material and the coverplates 58 are replaced and bolted in place.

The built-in hoist permits rapid access to the interior of the furnacechamber in case of product melt down or to clear any product jams thatmay occur. The access is obtained without the use of forklift truckswhich can damage the refractory sections and cause premature replacementof the furnace sections.

Further, the built-in hoist means provides a simple method of removingsections of the furnace where space requirements preclude the use ofmachinery such as forklift trucks to remove the furnace sections.

Reasonable variations and modifications are possible within the scope ofthe foregoing disclosure, drawings and appended claims without departingfrom the spirit of the invention.

The embodiments of an invention in which an exclu;

sive property or privilege is claimed are defined as follows:

1. In a billet heating furnace having:

a longitudinal heating chamber formed from refractory material includinga plurality of upper refractory sections;

an entrance end and an exit end in said heating chamber;

heating means spaced along the sides of said heating chamber for heatingbillets within said heating chamber by direct flame impingement of saidbillets;

means for passing billets through said heating chamber from saidentrance to said exit end;

a casing surrounding said furnace including a top Wall and side walls;

gas removal means for withdrawning and removing gases within saidfurnace through the top of-.said upper refractory section and throughsaid casing top wall;

the improvement which comprises:

track means within said casing above said upper refractory sectionextending longitudinally of said furnace;

hoist means movably supported by said track means so as to belongitudinally movable above said furnace;

a cable on said hoist having an end raisable and lowerable by saidhoist; and

means on said upper refractory section for engaging said end of saidcable, whereby raising of said cable by said hoist can lift a furnacesection engaged by said cable end to permit access to the interior ofsaid furnace.

2. A billet heating furnace according to claim 1 Wherein said gasremoval means comprises at least one exhaust aperture in an upperportion of said upper refractory section, said aperture extendingthrough said upper refractory section; exhaust conduits depending fromsaid casing top wall above and spaced from said aperture, at least abottom portion of said exhaust conduit being removable so as to permitsaid sections to be raisable and movable longitudinally of said furnaceover and above other of said sections.

3. A billet heating furnace according to claim 1 wherein each upperrefractory section has a top and depending sides; said engaging meanscomprise bars extending out of opposite of said sides of said refractorysections.

4. A billet heating furnace according to claim 3 wherein each refractorysection has a metal casing on the outer portion thereof, said metalcasing being fixed to said refractory sections by anchor means embeddedin the refractory sections and secured to said metal casing.

5. A billet heating furnace according to claim 4 wherein said metalcasings have brace members extending upwardly along the sides andlaterally of the top thereof,

fit

perpendicular to the surface of said casings, and brace bars extendinghorizontally between adjacent brace members on said sides of said metalcasing on each refractory section, said brace members being positionedabove and contacting said bars extending out of the sides of saidrefractory sections so as to reinforce said bars in said refractorysections.

-6. A billet heating furnace according to claim 1 wherein said trackmeans comprises two tracks extending longitudinally above and on eitherside of said heating chamber, and hoist means are movably supported oneach track so that said upper refractory sections can be supported oneach side as the same is raised.

7. In a billet heating furnace having:

a longitudinal heating chamber formed from refractory material includinga plurality of upper refractory sections;

an entrance end and an exit end in said heating chamber;

heating means at the sides of said furnace for heating billets withinsaid heating chamber as said billets pass through said heating chamber;

means for passing said billets through said heating chamber from saidentrance end to said exit end;

a casing, spaced from said refractory material, surrounding said furnaceand including a top wall and side walls;

gas removal means for Withdrawing and removing gases from within saidfurnace and through said upper refractory sections and through saidcasing;

the improvement which comprises:

hoist means within said casing and above said longitudinal heatingchamber adapted to engage each refractory section and raise said sectionto a position wherein direct access can be obtained to the interior ofsaid longitudinal heating chamber.

8. A billet heating furnace according to claim 7 wherein at least aportion of said side walls of said casing are removable for directaccess to the interior of said longitudinal heating chamber.

References Cited UNITED STATES PATENTS 1,656,963 1/ 1928 Stevens et al263-46 1,677,002 7/1928 Olson et al 89 2,386,565 10/1945 Nissim 110-99 X2,856,172 10/1958 Kautz 2636 3,428,301 2/ 1969 Chermely 263-46 CHARLESJ. MYHRE, Primary Examiner US. Cl. X.R. 263-46

